5 documents found, page 1 of 1

Conformational Study of Two Diasteroisomers of Vinylcatechin Dimers in a Methan...

Red wine possess anthocyanins (red colored pigments) and flavan-3-ol compounds (associated to the flavor). In an acidic environment, these compounds have higher reactivity due to the acidic character of the phenolic groups. Vinylcatechin adducts play a crucial role as intermediates in the formation mechanism of some anthocyanin-derived pigments (e.g., pyranoanthocyanins) during wine aging. They have gained incr...

Establishment of the Chemical Equilibria of Different Types of Pyranoanthocyani...

The chemical equilibria of the pyranomalvidin-3-glucosides linked to (+)-catechin, (-)-epicatechin, and catechol moieties (and the respective coumaroylglucoside Compounds) were established by means of UV-vis spectroscopy. The conjugated double bonds among pyranic rings C and D provide a higher electronic delocalization that prevents the nucleophilic attack of water at position 2. Consequently, besides flavylium...

Vinylcatechin Dimers Are Much Better Copigments for Anthocyanins than Catechin ...

The binding constants (K) for the interaction of three copigments (CP), two epimeric vinylcatechin dimers (CP1 and CP2), and catechin dimer B3 (CP3) with two pigments, malvidin-3-glucoside (oenin) and malvidin-3,5-diglucoside (malvin), were determined. The K values clearly show that both vinylcatechin dimers have much higher affinity for oenin and malvin than dimer B3: K(CP2) > K(CP1) >> K(CP3). Quantum mechani...

Pyranoanthocyanin Dimers: A New Family of Turquoise Blue Anthocyanin-Derived Pi...

In the present work, several compounds bearing similar spectroscopic features were found to occur in aged Port wines and respective sediments (lees). The data obtained revealed two new families of compounds with unique spectroscopic characteristics, displaying a wavelength of the maximum absorption at high wavelength in the visible spectrum at similar to 730 and similar to 680 nm. The structure of these pigment...

Comparação dos níveis de força inferior em jovens ginastas e alunos : 6, 7 e 8 ...